In the construction of buildings, bridges, and other man-made structures, it is well-known to place passive supports such as footers, piles, and other subsurface installations for supporting above ground structures. Subsurface supports can be generally classified in two types. Passive supports are those that require the earth around the subsurface support to first shift or move to mobilize the available tensile, bending, or shear capacities of the subsurface supports. Active supports are those that are pre-tensioned to prevent shifts in the earth.
It is known to provide ground strengthening by driving, drilling, or launching elongate reinforcing members, referred to as soil nails, into the ground in a pattern, thus improving the bulk properties of the ground. Soil nails in generally horizontal orientations are used to prevent shifting or other undesirable movement of a particular geological formation. Soil nails installed in vertical orientations can also add to the bearing capacity of a foundation and can be referred to also as micropiles. When soil nails are pretensioned, they can be referred to as tiebacks or tendons.
In some circumstances, the earth surrounding or under a man-made structure becomes unstable and therefore requires active supports, such as tie-backs, that are pre-tensioned subsurface installations used to restrain movement of the surrounding soil and rock. Recently, soil nails and tie-backs have been used to provide both temporary and permanent excavation support and slope stabilization.
Mountainous terrain provides a challenge for road designers to provide the required roadway width. Two significant regulatory changes over recent years have made roadway construction and maintenance particularly challenging for mountainous areas. The first regulatory change includes Federal and State Highway Safety Standards in which new roads must comply with stricter specifications regarding the size of the roadway width and shoulder, as well as other design specifications, such as the allowable slope, grade, and radius for curves. In some cases, if an existing roadway is repaired or modified, it may have to comply with the more strict design specifications therefore requiring the road to be widened.
The other significant regulatory change is limitations on disruption of the surrounding environment in order to reduce the environmental impact of roads located in State or Federally protected lands. Road widening efforts such as blasting or significant earth removal may not comply with environmental impact standards, thus preventing or greatly inhibiting the ability to widen a roadway.
Therefore, there is a need to provide a system and method for increasing the width of a roadway that complies with current Federal and State regulatory schemes. There is also a need to provide such a system and method that is not cost prohibitive and is relatively easy to install. There is yet another need to provide a system and method for increasing a roadway width in which the solution is adaptable for diverse environments.